JPH0543541B2 - - Google Patents

Description

Detailed Description of the Invention A. Object of the Invention (1) Industrial Field of Application The present invention comprises a cylinder body and a piston that slides into a cylinder hole of the cylinder body and defines a hydraulic chamber within the cylinder hole. This is a relief port valve for a master cylinder that defines a replenishment oil chamber communicating with an oil tank in the cylinder hole by the intermediate portion of the piston, and is bored in the piston so as to communicate between the oil pressure chamber and the replenishment oil chamber. a poppet valve that can open and close a relief port; a valve spring that biases the poppet valve in the closing direction; This invention relates to an improvement in a valve opening rod that faces the valve to open the valve.

(2) Prior art This type of relief port valve is, for example,
This is already known as disclosed in Japanese Patent No. 32562.

(3) Problems to be solved by the invention In the conventional relief port valve of this type, the valve opening rod is fixed to the cylinder body, and the valve opening rod is inserted into the through hole of the piston into which the valve opening rod is loosely inserted. It is formed into a long hole so as not to interfere with reciprocating motion. Therefore,
Since the elongated hole must have a long diameter longer than the sliding stroke of the piston, the piston itself has to be made long.
When this type of relief port valve is adopted, there is a problem in that the master cylinder becomes long.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide the above-mentioned relief port valve that can be used even with a relatively short piston and can contribute to shortening the master cylinder.

B. Structure of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention provides a bearing that is fixed to a cylinder body and slidably supports a piston, and a bearing that is connected to a valve opening rod. In addition, the stopper ring attached to the piston so as to come into contact with the bearing and restrict the retraction limit of the piston is formed of a material that exerts an attractive force on each other when the two come into contact.

(2) Action At the piston's retraction limit, the stopper ring is held in the abutting position with the fixed bearing by mutual attraction, so even when the piston is moving forward, the stopper ring is held by the adhesive force of the oil attached to the piston. The valve-opening rod can be prevented from moving within the range of play in the through-hole of the piston, and the valve-opening rod can be prevented from moving within the range of play in the through-hole of the piston.
Therefore, as the piston moves forward, the poppet valve is immediately released from the valve opening rod and moved to the closing position by the valve spring, thereby closing the relief port.

After the poppet valve is closed, when the valve opening rod is pressed forward by the rear wall of the through hole due to the subsequent advancement of the piston, the stopper ring is separated from the bearing by overcoming the suction force, so that the valve is opened. The piston can be moved forward with the rod. As a result, the play of the valve opening rod in the through hole of the piston is only required to be extremely small.

(3) Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The master cylinder M shown in FIG. A front piston 2 ₁ and a rear piston 2 ₂ are provided in the cylinder hole 1a.
are slid together in series, a front hydraulic chamber 3 ₁ is defined between the front piston 2 ₁ and the front end wall of the cylinder 1a, and a rear hydraulic chamber 3 ₂ is defined between both pistons 2 ₁ and 2 ₂ . Two brake hydraulic circuits are connected to output ports 4 ₁ and 4 ₂ connected to the hydraulic chambers 3 ₁ and 3 ₂ , respectively.

Each piston 2 ₁ , 2 ₂ is provided with a cup seal 5 ₁ , 5 ₂ that is in close contact with the cylinder hole 1a, and the intermediate portion of each piston 2 1 , 2 2 has front and rear supply oil chambers 6 ₁ , 6 ₂ in the cylinder hole 1a. It has a small diameter to define the area. Oil holes 7 that communicate these supply oil chambers 6 ₁ , 6 ₂ with the backs of the cup seals 5 ₁ , 5 _2
1 and 7 ₂ are drilled into each piston 2 ₁ and 2 ₂ .

The front hydraulic chamber 3 ₁ includes a return spring 8 ₁ that urges the front piston 2 ₁ in the backward direction, and both pistons 2 ₁ ,
_{A return spring 8 2 is} provided between each of the pistons 2 2 to urge the rear piston 2 ₂ in the backward direction.

At the top of the cylinder body 1, there is a front oil supply chamber _61.
A cylindrical auxiliary oil tank 9 is integrally provided adjacent to the auxiliary oil tank 9, and a main oil tank 10 made of synthetic resin is fitted into the upper end of the auxiliary oil tank 9 and connected thereto.

Inside the auxiliary oil tank 9 is a bulkhead 1 that is integrated with the cylinder body 1.
1 into front and rear oil reservoir chambers 9 ₁ and 9 ₂ , and the front oil reservoir chamber 9 ₁ is connected to the front supply oil chamber 6 ₁ through a through hole 12 ₁ penetrating its bottom wall. The front replenishment oil chamber 6 ₁ communicates with a through hole 13 ₁ that passes laterally through the middle part of the front piston 2 ₁ , and this through hole 13 ₁ .
It communicates with the front hydraulic chamber 3 ₁ through a relief port 14 ₁ that passes through the center of the piston 2 ₁ and opens at the front surface thereof. The through hole 13 ₁ is formed with a major axis longer than the sliding stroke of the front piston 2 ₁ in the axial direction of the front piston 2 ₁ .

A conventional relief port valve V ₁ is provided in the front piston 2 ₁ to open and close said relief port 14 ₁ . This relief port valve V ₁ is composed of a valve case 15 ₁ , a poppet valve 16 ₁ , a valve spring 17 ₁ and a valve opening rod 18 ₁ .

The valve case 15 ₁ has a cup shape with a valve seat 19 ₁ on the bottom wall, and a seal is attached to the front end of the front piston 2 ₁ so that the center hole of the valve seat 19 ₁ matches the relief port 14 ₁ . It is fitted through the member ₂₀₁ .

The poppet _valve 16 ₁ consists of a rubber umbrella part 21 ₁ and a valve rod _{22 2 that} supports the umbrella part 21 ₁ . ₁ is arranged so as to be loosely inserted into the relief port ₁₄₁ .

The valve spring 17 ₁ is attached to the valve case 15 ₁ so as to bias the poppet valve 16 ₁ toward the valve seat 19 ₁ , that is, in the valve closing direction.

The valve opening rod 18 ₁ is connected to the through hole 13 ₁ of the front piston 2 ₁
The poppet valve 16 1 is fixed to the cylinder body 1 through the rear end of the valve rod 22 ₁ so as to receive the rear end of the valve rod 22 ₁ so as to open the poppet valve 16 ₁ at the retraction limit of the front piston 2 1 .

On the other hand, the rear oil reservoir chamber 9 ₂ communicates with the rear replenishment oil chamber 6 ₂ via a through hole 12 ₂ passing through the upper wall of the cylinder body 1, and the rear replenishment oil chamber 6 ₂ also communicates with the rear piston 2 _{2 .} A through hole 13 ₂ that passes through the middle part of the
and communicates with the rear hydraulic chamber 3 ₂ via a relief port 14 ₂ that passes through the center of the rear piston 2 2 and opens at _the front surface thereof.

The rear piston ₂₂ includes a piston portion 24 equipped with the cup seal ₅₂ , and a rod portion 2 connected to the rear end of the piston portion 24 via a connecting ring 26.
5, all of which are made of non-magnetic material. The rod portion 25 is slidably supported via a seal member 28 on a bearing 27 made of a magnetic material that is fitted into the rear end of the cylinder body 1 concentrically with the cylinder hole 1a, and also has a booster (not shown). The rear end is connected to the output rod of the device. The through hole ₁₃₂ is bored in this rod portion.

A relief port valve V ₂ of the present invention is provided on the rear piston 2 ₂ to open and close the relief port 14 ₂ . This relief port valve V ₂ is valve box 15
₂ , poppet valve 16 ₂ , valve spring 17 ₂ , valve opening rod 18 ₂
and a stopper ring 29.

The valve case 15 ₂ has a cup shape with a valve seat 19 ₂ on the bottom wall, and a seal member is installed at the front end of the rear piston 2 ₂ so that the center hole of the valve seat 19 ₂ matches the relief port 14 ₂ . It is fitted through ₂₀₂ .

The poppet valve 16 ₂ consists of a rubber umbrella part 21 ₂ and a valve rod 22 ₂ that supports the umbrella part 21 ₂ , with the umbrella part 21 ₂ facing the valve seat 19 ₂ and the valve rod 22 ₂ . is arranged so as to be loosely inserted into the relief port ₁₄₂ .

The valve spring 17 ₂ connects the poppet valve 16 ₂ to the valve seat 19 ₂
The valve case _{152 is attached to the valve case 152} so as to be biased toward the valve closing direction.

The valve opening rod 18 ₂ is the valve rod 22 ₂ of the poppet valve 16 ₂
It is loosely inserted into the through hole 13 ₂ of the rear piston 2 ₂ so that the rear end can be pushed or moved away from them.

As shown in FIG. 2, the stopper ring 29 includes a stopper ring body 29a made of synthetic resin and an annular magnet 29 fixed to the rear end of the stopper ring body 29a.
b, and the magnet 29b is connected to the bearing 27.
It is slidably fitted into the rod portion 25 of the rear piston ₂₂ , facing the front end of the piston. This stopper ring 2
9 can restrict the backward limit of the rear piston 22 by contacting the bearing 27 and receiving the piston portion ₂₄ , and at this time, the valve opening rod ₁₈₂ receives the rear end of the valve rod ₂₂₂ . The poppet valve ₁₆₂ is held in an open state.

Next, the operation of this embodiment will be explained. When the rear piston 2 ₂ is at its retracting limit, the stopper ring 29 is moved toward the bearing 27 by the attraction force of the magnet 29b to the bearing 27.
Therefore, when the rear piston ₂₂ is moved forward by the operation of a booster (not shown), the stopper ring 29 initially resists the adhesive force of the hydraulic oil adhering to the rear piston ₂₂ . The valve opening rod 18 2 remains in the abutting position with the bearing 27 and can reliably prevent movement of the valve opening rod 18 ₂ within the range of play in the through hole 13 ₂ . Therefore, the poppet valve 16 ₂ is immediately released from the valve opening rod 18 ₂ and is pressed against the valve seat 1 by the valve spring 17 ₂ .
9 ₂ to the seated position, that is, the valve closing position, and the relief port 14 ₂ can be closed. When the poppet valve 16 ₂ closes, the following rear piston 2 ₂
As the valve opening rod ₁₈₂ moves forward, the opening rod 182 is pushed forward by the rear wall of the through hole ₁₃₂ , and the stopper ring 29 is pulled away from the bearing ₂₇ by overcoming the attractive force of the magnet 29b. Piston 2 ₂ moves forward.

This forward movement of the rear piston 2 ₂ generates hydraulic pressure in the rear hydraulic chamber 3 ₂ , and this hydraulic pressure is output from the output port 4 ₂ to operate the corresponding wheel brake.

On the other hand, the front piston 2 ₁ moves forward in response to the forward force of the rear piston 2 ₂ applied to the return spring 8 ₂ and the hydraulic pressure generated in the rear hydraulic chamber 3 ₂ , and accordingly the poppet valve 16 ₁ opens. It is released from the valve stem 18 ₁ and moved to the closed position by the valve spring 17 ₁ to close the relief port 14 ₁ , so that hydraulic pressure is generated in the front hydraulic chamber 3 ₁ due to the subsequent advancement of the front piston 2 ₁ .
The hydraulic pressure is outputted from the output port ₄₁ to operate the corresponding wheel brake. During this time, the valve opening rod 18
₁ moves relatively within the through hole 13 ₁ and does not hinder the forward movement of the front piston 2 ₁ .

As is clear from the above operation, in the relief port valve V ₂ of the present invention, the relative displacement between the valve opening rod 18 ₂ and the rear piston 2 ₂ is smaller than that of the conventional relief port valve.
It is extremely smaller than the relative displacement between the valve opening rod 18 ₁ and the front piston 2 ₁ at V ₁ , and the play of the valve opening rod 18 ₂ in the through hole 13 ₂ is suppressed to a small extent, and the cylinder hole 1a of the rear piston 2 ₂ is It is possible to significantly reduce the length occupied by the

If the booster is deactivated, both pistons 2 ₁ ,
2 ₂ is returned to a predetermined retraction limit by the return force of each return spring 8 ₁ , 8 ₂ , and in the return process, the hydraulic chambers 3 ₁ ,
3 ₂ is depressurized, the outer periphery of the cup seals 5 ₁ and 5 ₂ bends forward due to the pressure difference between the front and rear, creating a gap between the inner surface of the cylinder hole 1a and the gap between each piston 2 ₁ and 2 ₂ . Hydraulic oil is supplied from the supply oil chambers 6 ₁ , _{6 2 to} the hydraulic chambers 3 ₁ , 3 2 _through the oil holes 7 1 , 7 ₂ . At that time, if excessive replenishment is performed, the excess oil is supplied to the replenishing oil through the relief ports 14 ₁ , 14 ₂ which are opened by the poppet valves 16 ₁ , 16 ₂ when each piston 2 ₁ , 2 ₂ returns to the retraction limit. room 6
_1,6 Returned to ₂ .

In addition, in the relief port valve _V2 of the present invention,
A magnet is attached to the bearing 27, and the stopper ring 2
9 can also be made of a magnetic material.

C. Effects of the Invention As described above, according to the present invention, there is a bearing that is fixed to the cylinder body and slidably supports the piston, and a bearing that is connected to the valve opening rod and comes into contact with the bearing to limit the retraction of the piston. The stopper ring attached to the piston is made of a material that exerts mutual attraction when they come into contact with each other, so even if the play of the valve opening rod in the piston's through hole is small, the piston's During forward movement, the opening rod positively releases the poppet valve to close it and does not impede the movement of the piston in any way. Therefore, it is possible to contribute to shortening the piston and, by extension, shortening the master cylinder.

Moreover, since the valve opening rod can reliably release the poppet valve, it is possible to set the set load of the valve spring to a small value, thereby reducing the closing pressure of the poppet valve as much as possible and improving its durability. You can also try it out.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a longitudinal cross-sectional side view of a tandem type master cylinder, and FIG.
The figure is an enlarged view of the main part of the relief port valve of the present invention in the master cylinder, and FIG. 3 is an exploded perspective view of the main part. M...Master cylinder, _V2 ...Relief port valve, 1...Cylinder body, 1a...Cylinder hole, 2 ₂ ...Piston, 3 ₂ ...Hydraulic chamber, 6 ₂ ...
Supply oil chamber, 13 ₂ ... Through hole, 14 ₂ ... Relief port, 15 ₂ ... Valve box, 16 ₂ ... Poppet valve, 1
7 ₂ ... Valve spring, 18 ₂ ... Valve opening rod, 27 ... Bearing, 29 ... Stopper ring, 29a ... Stopper ring body, 29b ... Magnet.

Claims (1)

[Claims] 1 Consists of a cylinder body and a piston that slides into a cylinder hole of the cylinder body to define a hydraulic chamber within the cylinder hole, and the intermediate portion of the piston defines a replenishment oil chamber that communicates with an oil tank within the cylinder hole. A poppet valve, which is a relief port valve of a master cylinder and which can open and close a relief port bored in a piston so as to communicate between a hydraulic chamber and a replenishment oil chamber, and a poppet valve that biases the poppet valve in the valve closing direction. A valve spring consisting of a valve spring and a valve opening rod that is loosely fitted into a through hole passing through the middle part of the piston in the lateral direction and faces the poppet valve in order to open the poppet valve at the retraction limit of the piston. A bearing that is fixed and slidably supports the piston, and a stopper ring that is connected to the valve opening rod and that is attached to the piston so as to abut the bearing and restrict the retraction limit of the piston. A relief port valve for a master cylinder, characterized in that it is made of a material that exerts mutual attraction when they come into contact.